What's eating my tsusima holly fern?

Tsusima Holly Fern (Polystichum tsussimense) is a compact Asian fern grown as a houseplant or sheltered garden plant. Indoors, scale insects and mealybugs are the main threats, hiding along frond midribs. Spider mites can appear in hot, dry indoor air. Fungus gnats breed in overly moist potting mix.

Brown or tan shell-like bumps along frond midribs and stems; yellowing fronds and sticky honeydew. Scrape off manually with a soft toothbrush; apply horticultural oil or neem oil to smother remaining crawlers. Repeat every 10 days.

White cottony deposits at frond bases and in leaf axils; fronds may wilt. Dab with isopropyl alcohol on a cotton swab; treat with neem oil spray; isolate plant to prevent spread.

Fine webbing on frond undersides; tiny stippled bronzing of frond tissue. Increase humidity; mist fronds and wipe with a damp cloth; apply insecticidal soap or neem oil spray, targeting undersides.

Adults hover around the pot; larvae damage fine roots causing slow decline. Allow the top inch of soil to dry between waterings; apply Bti drench (e.g., Gnatrol); use yellow sticky traps for adults.